The formation of decubitus ulcers (bedsores) on patients who are confined to bed for long periods of time is a persistent problem, in spite of many attempts utilizing a variety of approaches to solving this problem. Flotation beds such as water beds, while effective, are very expensive. One alternative to a flotation bed is the mattress disclosed in U.S. Pat. No. 4,163,297 as being formed by a series of partially-filled pillows, each in contact with and supported by the immediately adjacent pillow(s), all disposed on their edges transversely to an underlying bed. The present applicant has devised a more flexible and relatively inexpensive patient support system which, by suitably positioning the component cushions, eliminates pressure on the patient's buttocks and heels, the sites at which bedsores form most persistently.